The present invention relates to a door construction. More specifically, the invention is directed to a door which is slidable between open and closed conditions.
The invention is particularly applicable to corrugated metal doors of the type used on railway freight cars and will be particularly described with reference thereto. However, it will be appreciated by those skilled in the art that the invention has broader applications and is adaptable to use on doors of other types and in other environments.
Rectangular metal doors of a known type used on railroad cars include a generally rectangular frame having top, bottom, and opposed side door frame members. Corrugated metal panels are secured to these frame members for completing the basic door construction. In most conventional railway cars, the frame members and corrugated panels are riveted together. However, the manufacture of riveted door constructions is very time consuming and can take anywhere from two to three weeks from start to finish.
It has been determined that a welded car door is much more efficient to manufacture since it only takes approximately one-half the time of a riveted door. This result occurs because the number of fabricating steps or operations is reduced. Even the known welded rail car doors, however, are not adequately reinforced to enable them to absorb the impact loads to which a railway car door is typically subjected.
Moreover, conventional rail car doors, whether riveted or welded, also are not sufficiently sturdy to withstand internally applied loads. Theoretically, car doors are not intended or supposed to be internally loaded. However, when cargo shifts inside the rail car, it can and does internally load the doors. For this reason, it has been considered desirable to stiffen rail car doors for enabling them to bear various internal loads which are sometimes imposed thereon.
Sliding doors of conventional railroad freight cars are typically held closed by an elongated hasp which is rotatably mounted near the leading edge of one sliding door, and extends beyond the door to engage a locking mechanism mounted on the door jamb or on a second sliding door. The hasp is usually mounted through an eye at one end thereof which is positioned in a hasp fastener thus enabling the hasp to rotate both horizontally and vertically about the fastener. Since these door hasps are subjected to a good deal of punishment and damage in ordinary use, it is often necessary to replace them.
Conventional hasp fasteners are secured to rail car doors by rivets and welds. With this type of construction, it becomes necessary to chisel off the heads of the rivets to remove the hasp fastener and damaged hasp, and then re-rivet the fastener to the door when the new hasp has been installed. Alternately, the eye of the broken hasp can be cut open with a torch. In this case, the replacement hasp also has to be cut open, positioned around the hasp fastener, twisted back into shape and re-welded. Yet another method of removing broken hasps is to cut the link of the hasp fastener for allowing removal of the damaged hasp. A new hasp is then substituted, and the link member is bent back into shape and re-welded. As is evident, all of these replacement methods are very time consuming and serious disadvantages may arise with regard to the quality of the connection of the hasp to the fastener or of the fastener to the door.
A more recent hasp replacement method utilizes a kit including a member which partially defines a hasp eye and is sized to fit loosely about the existing hasp retaining link. An eye completion member is arranged to mate with the first member to form a replacement hasp when affixed thereto by welding. Together, these two members form a replacement hasp by positioning the partial eye defining member about the link, mating the eye completion member therewith, and then welding the two members together. However, this method necessitates use of a more expensive two component hasp member in place of the conventional, and less expensive, one-piece hasp.
Accordingly, it has been considered desirable to develop a new and improved rail car door and a hasp assembly therefor which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.